Skip to Main Content
ASM Failure Analysis Case Histories

Handbook of Case Histories in Failure Analysis

Edited by
Khlefa A. Esaklul
Khlefa A. Esaklul
Search for other works by this author on:
ASM International
Volume
2
ISBN electronic:
978-1-62708-215-0
Publication date:
1993
Book Chapter

Shafts

Published:
1993

Abstract

A forged 4140 steel shaft that connected two runners in a hydroturbine failed catastrophically after approximately 5900 h of service. The runner and the mating section of the broken shaft were examined and tested by various methods. The results of the analyses indicated that the shaft failed by torsional fatigue starting at subsurface crack initiation sites. The forging contained regions of crack like flaws associated with particles rich in chromium, manganese, and iron. Fracture features indicated that the fatigue cracks propagated under a relatively low stress.

Abstract

A crane long-travel worm drive shaft was found to be chipped during unpacking after delivery. Chemical analysis showed that the steel (EN36A with a case depth of 1 mm, or 0.04 inch did not meet specifications. Magnetic particle inspection revealed a crack on the side of the shaft opposite the chip. Metallographic examination indicated that the case depth was approximately 2 mm (0.08 in.) and that a repair weld of an earlier chip had been made in the cracked area. The chipping was attributed to excessive case depth and rough handling. It was recommended that the shaft be returned to the manufacturer and a replacement requested.

You do not currently have access to this content.
Don't already have an account? Register

1993. "Shafts", Handbook of Case Histories in Failure Analysis, Khlefa A. Esaklul

Download citation file:


Close
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal